Typically, staircases are completely produced on site with the various wood components being cut to size as the staircase is progressively erected on site.
Also, it has been proposed to completely assemble a staircase in the factory such that a pre-assembled staircase is delivered to the construction site for direct and easy installation thereat. Such a modular staircase is disclosed in Canadian Patent Application No. 2,149,981 naming Raymond Couture as inventor and laid-open for public inspection on Nov. 24, 1995.
Furthermore, in Canadian Patent Application No. 2,276,988, also naming Raymond Couture as inventor, and laid-open for public inspection on Dec. 30, 1999, a modular staircase is proposed, which includes a permanent framing made of metallic stringers and vertically extending step supports that are secured along the stringers. Each step support includes upper and front flanges adapted to be secured respectively to a tread and to a riser of each step of the staircase. If the staircase has a partly exposed side, various decorative or finishing wooden components, including treads, risers, false or decorative stringers, mouldings, etc., are provided to cover any exposed structural metallic framework and particularly the stringers.
Moreover, in U.S. Pat. No. 4,422,270 naming Leopold Lapointe and Donat Pelletier as inventors and issued on Dec. 27, 1983, a modular, self supporting flight of stairs is proposed. The flight of stairs described therein comprises at least one pair of stringer units for supporting at least one tread thereon and bolted thereto. The stringer units each comprise a side plate and a fixation plate extending outwardly therefrom and parallel thereto for fixing a fixation of a first unit to a side plate of an adjacent unit by riveting or bolting. A two-part stringer unit comprising intersecting oblong slots allows for step height adjustments.
In U.S. Pat. No. 2,593,683, naming G. W. Lyons as inventor, and issued on Apr. 22, 1953, a vertically adjustable staircase is proposed. The flight of stairs described therein comprises sectional stringers formed of prefabricated sheet metal tread-supporting plates, each plate comprising a vertical body portion, two vertical and parallel longitudinal flanges perpendicular thereto and a horizontal rectangular top flange for supporting a tread thereon and bolted thereto. One of the longitudinal flanges of a given plate comprises a plurality of sets of perforated holes for combining with a set of corresponding perforated holes in an adjacent longitudinal flange of an adjacent plate thereby providing adjustable fastening means therefor.
Furthermore, PCT Patent Publication No. WO 2005/090705-A1 published on Sep. 29, 2005 in the name of Raymond Couture, discloses staircases that are constructed of modular stringers for the on-site installation of the staircases in a residential, commercial or industrial setting. Kits for erecting the staircases include matingly or cooperatively coupling step support units defining the staircase stringers, a set of steps adapted to be mounted thereon, as well as various finishing elements and modules to provide a finished look to the completed staircases. The staircases include self-supporting staircases, linear staircases, curling or spiralling staircases and adjustable variations thereof.
Therefore, it is desirable to provide a modular stairway system, typically in the form of a kit, which can be assembled to erect a stairway on site.